Spiro(indolino)oxazine compounds have been found to be useful for imparting photochromic properties to a polymeric host material. Examples of spirooxazine and their use in photochromic lenses have been reviewed by Crano et al. in Applied Photochromic Polymer Systems (C. B. McArdle, Ed.) Blackie & Sons, Glasgow, London, 1992, pp. 31-76. As a rule, the unsubstituted spiroindolinonaphthoxazines give a rather low optical density of the blue color on exposure to light.
Several U.S. patents describe spiro(indoline)naphtho(2,1-b)(1,4)oxazine compounds (see for example U.S. Pat. Nos. 4,959,471 (Melzig), 4,913,544, 5,446,149, 5,446,150, 5,446,151 (Rickwood et al.), 5,186,867 (Castaldi et al.), 5,405,958 (Van Gemert), 5,936,016 (Lareginie et al.), 6,004,486 and 6,030,555 (You-Ping Chan)) that are said to give enhanced optical density on exposure to sunlight. The enhancement of the photoinduced optical density was achieved mainly by introducing electron-donor or -acceptor substituents in the naphthalene moiety of the molecule, while the absorption maximum of the colored form remains in the region of 570-630 nm.
U.S. Pat. Nos. 4,851,530 and 5,833,885 (Rickwood et al) describe spirooxazines showing substantial change in the kinetic and spectral properties of spirooxazines by modification of the 1-position in the indoline ring with the absorption maxima of the photoactivated form shorter than 570 nm (mainly red). PCT Publication No. WO 99/20630 describe photochromic spiro (indoline)naphtho( 1,2-b)(1,4)oxazine compounds.
The present invention relates to novel spiro(indoline)naphtho(2,1-b) (1,4)oxazine and spiro(indoline)naphtho(1,2-b)(1,4)oxazine compounds that have particular substituents on the indoline and/or on the naphthalene part of the molecule. None of the publications mentioned above describe the compounds of the present invention.